1. Field of the Invention
The present invention relates to a technique for enhancing the dustproofing capability of a power tool having ventilation holes in its outer frame.
2. Description of the Related Art
There is a tendency that the current fed into electric motors is increased in order to offer smaller power tools with higher output power. Concomitantly, there is a tendency that the stator and rotor are directly supported by the outer frame portion to enlarge the flow passage for cooling wind, as described in JP-A-2002-254337, to suppress generation of heat from the motor.
Furthermore, there is a tendency that permanent magnets having stronger magnetic flux are adopted in a power tool using a DC motor, in order to offer a smaller motor with higher output power.